ModellingAmmoniaBasedAerationControlinRealTimewithOnline

InstrumentationHach CityofSanDiegoDaveCommons RobertRelphBobDabkowski GeorgeWendorfKevinMenningMelodyWhite

NewEnglandWaterEnvironmentAssociation2018AnnualConferenceBoston,MassachusettsWednesday,January24,2018

Problem:OversizedBlowers

• Expenseofenergy• Wasteofdissolvedoxygen• Flocshearing/settleabilityissues

• Whatsizeblowersdowereallyneed?• Whatisthemostefficientoperation?• Howquickisthepayback?

Solution:ModelABACinRealTime

• Ammoniabasedaerationcontrol(ABAC)• Usejustenoughdissolvedoxygentonitrifytodesiredsetpoint• AssumesBODisremovedbeforenitrificationiscomplete

• HachRealTimeControllerforNitrification(RTC-N)• CalculatestheoptimalDOconcentrationforABAC• Useforeithermodellingorcontrollingaprocess• Mostutilitiesdon’thavemodellingsoftware

• ActualDO– “Optimal”DO=$$Savings$$

Influent

ReturnActivated

Slud

ge

“NormalOperation”:Addmoreairthannecessary

0

30

20

10

Ammon

iaCon

centratio

nmg/L

AerationBasin

FinalClarifier

WasteActivatedSludge

MixedLiquor

WASTEDAERATION

FlocshearAerobicDigestionWastedEnergyRecycleHighDO

ImaginetheAerationBasinasagraph…

AMMONIABASEDAERATIONCONTROL(ABAC)

Influent

ReturnActivated

Slud

ge

“NormalOperation”:Addmoreairthannecessary

0

30

20

10

Ammon

iaCon

centratio

nmg/L

“ABACControl”:Addtheperfectamountofair

AerationBasin

FinalClarifier

WasteActivatedSludge

MixedLiquor

WASTEDAERATION

FlocshearAerobicDigestionWastedEnergyRecycleHighDO

ImaginetheAerationBasinasagraph…

ProcessControl|Energy$aving$|Consistency

CONSISTENTEFFLUENTLessShearLowerDO

NoDigestion

AMMONIABASEDAERATIONCONTROL(ABAC)

• Typicalinstallation• AerationInfluent&EffluentAmmoniaConcentration• TSSConcentration&LDO(temperaturerequired)• UseexistingDOControlsystem

NH4-N

Flow

sc1000

RTCController

Aeration

NH4-N

PLC

LDO TSS

RTC-Nnitrificationcontroller

HachRTC-NModellingSystemHachRTC-N

Influent&effluentammonia

NeededvsMaximumNitrificationRate

SRT,NitrifierConcentration,Growth&Decay

ABACDOvsActualDO

Resultsfromrealtimemodelling

Column1 Column2AverageActualDissolvedOxygen

Concentration(mg/L)3.10

AverageOptimalDissolvedOxygenConcentration(mg/L)

1.22

AveragePotentialEnergySavings(%)

24.2%

Conclusions

• SignificantenergysavingspossiblewithABAC(65.8%)alongwithenhanceddenitrification• NeededvsMaximumnitrificationrateallowsoperatorstomanagesidestreams• Nitrificationrate,Nitrifierconcentration,OptimalDOdatawillhelpengineeringdesignappropriatelysizedsystem• HachRTC-Nsystemsuitableformodellingorcontrolofunitprocesses